1. Field of the Invention
The present invention relates to an electromagnetic clutch constructed so that friction-engaging elements are brought into close contact with one another by the attracting force of a solenoid.
2. Description of the Related Art
The solenoid of an electromagnetic clutch may include a coil housing which is disposed at a predetermined distance around an outer periphery of a coil having a conductor wire wound around an iron core, so that an armature is attracted to the coil housing by a magnetic force generated by supplying an electric current to the coil to bring the friction engaging elements into engagement with one another.
To reliably attract the armature, while minimizing the electric power consumed by the solenoid, it is necessary to decrease the magnetic resistance of a magnetic closed circuit formed around the outer periphery of the coil and to keep the leakage of a magnetic flux from the magnetic closed circuit to a minimum.